diff --git a/src/bytecode.c b/src/bytecode.c
index 40977799bf..ce1a7bd254 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -39,6 +39,7 @@ along with GNU Emacs. If not, see . */
#ifndef BYTE_CODE_SAFE
# define BYTE_CODE_SAFE false
#endif
+#define unlikely(expr) (__builtin_expect (expr, 0))
/* Define BYTE_CODE_METER to generate a byte-op usage histogram. */
/* #define BYTE_CODE_METER */
@@ -404,7 +405,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
int op;
enum handlertype type;
- if (BYTE_CODE_SAFE && ! (stack_base <= top && top < stack_lim))
+ if (unlikely (BYTE_CODE_SAFE && ! (stack_base <= top && top < stack_lim)))
emacs_abort ();
#ifdef BYTE_CODE_METER
@@ -664,9 +665,9 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
op_branch:
op -= pc - bytestr_data;
op_relative_branch:
- if (BYTE_CODE_SAFE
+ if (unlikely (BYTE_CODE_SAFE
&& ! (bytestr_data - pc <= op
- && op < bytestr_data + bytestr_length - pc))
+ && op < bytestr_data + bytestr_length - pc)))
emacs_abort ();
quitcounter += op < 0;
if (!quitcounter)
@@ -1397,7 +1398,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
number of cases is less, which uses a simple vector for linear
search as the jump table. */
Lisp_Object jmp_table = POP;
- if (BYTE_CODE_SAFE && !HASH_TABLE_P (jmp_table))
+ if (unlikely (BYTE_CODE_SAFE && !HASH_TABLE_P (jmp_table)))
emacs_abort ();
Lisp_Object v1 = POP;
ptrdiff_t i;
@@ -1426,7 +1427,7 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
if (i >= 0)
{
Lisp_Object val = HASH_VALUE (h, i);
- if (BYTE_CODE_SAFE && !FIXNUMP (val))
+ if (unlikely (BYTE_CODE_SAFE && !FIXNUMP (val)))
emacs_abort ();
op = XFIXNUM (val);
goto op_branch;
@@ -1436,8 +1437,8 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
CASE_DEFAULT
CASE (Bconstant):
- if (BYTE_CODE_SAFE
- && ! (Bconstant <= op && op < Bconstant + const_length))
+ if (unlikely (BYTE_CODE_SAFE
+ && ! (Bconstant <= op && op < Bconstant + const_length)))
emacs_abort ();
PUSH (vectorp[op - Bconstant]);
NEXT;
diff --git a/src/xdisp.c b/src/xdisp.c
index a88fc698b8..9872f69cb0 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -344,7 +344,8 @@ along with GNU Emacs. If not, see . */
/* Holds the list (error). */
static Lisp_Object list_of_error;
-
+#define UNLIKELY(expr) (__builtin_expect (expr, 0))
+#define LIKELY(expr) (__builtin_expect (expr, 1))
#ifdef HAVE_WINDOW_SYSTEM
/* Test if overflow newline into fringe. Called with iterator IT
@@ -8322,7 +8323,7 @@ compute_stop_pos_backwards (struct it *it)
reseat_1 (it, pos, false);
compute_stop_pos (it);
/* We must advance forward, right? */
- if (it->stop_charpos <= charpos)
+ if (UNLIKELY (it->stop_charpos <= charpos))
emacs_abort ();
}
while (charpos > BEGV && it->stop_charpos >= it->end_charpos);
@@ -8371,7 +8372,7 @@ handle_stop_backwards (struct it *it, ptrdiff_t charpos)
it->current.string_pos = string_pos (charpos, it->string);
compute_stop_pos (it);
/* We must advance forward, right? */
- if (it->stop_charpos <= it->prev_stop)
+ if (UNLIKELY (it->stop_charpos <= it->prev_stop))
emacs_abort ();
charpos = it->stop_charpos;
}
@@ -11443,7 +11444,7 @@ pop_message_unwind (void)
void
check_message_stack (void)
{
- if (!NILP (Vmessage_stack))
+ if (UNLIKELY (!NILP (Vmessage_stack)))
emacs_abort ();
}
@@ -15495,7 +15496,7 @@ set_cursor_from_row (struct window *w, struct glyph_row *row,
/* Need to compute x that corresponds to GLYPH. */
for (g = row->glyphs[TEXT_AREA], x = row->x; g < glyph; g++)
{
- if (g >= row->glyphs[TEXT_AREA] + row->used[TEXT_AREA])
+ if (UNLIKELY (g >= row->glyphs[TEXT_AREA] + row->used[TEXT_AREA]))
emacs_abort ();
x += g->pixel_width;
}
@@ -16827,9 +16828,9 @@ redisplay_window (Lisp_Object window, bool just_this_one_p)
/* Some sanity checks. */
CHECK_WINDOW_END (w);
- if (Z == Z_BYTE && CHARPOS (opoint) != BYTEPOS (opoint))
+ if (UNLIKELY (Z == Z_BYTE && CHARPOS (opoint) != BYTEPOS (opoint)))
emacs_abort ();
- if (BYTEPOS (opoint) < CHARPOS (opoint))
+ if (UNLIKELY (BYTEPOS (opoint) < CHARPOS (opoint)))
emacs_abort ();
if (mode_line_update_needed (w))
@@ -19318,9 +19319,9 @@ try_window_id (struct window *w)
adjust_window_ends (w, last_text_row, false);
eassert (w->window_end_bytepos >= 0);
}
- else if (first_unchanged_at_end_row == NULL
- && last_text_row == NULL
- && last_text_row_at_end == NULL)
+ else if (LIKELY (first_unchanged_at_end_row == NULL
+ && last_text_row == NULL
+ && last_text_row_at_end == NULL))
{
/* Displayed to end of window, but no line containing text was
displayed. Lines were deleted at the end of the window. */
@@ -21015,7 +21016,7 @@ find_row_edges (struct it *it, struct glyph_row *row,
which puts the iterator at the beginning of the next line, in
the logical order. */
row->maxpos = it->current.pos;
- else if (max_pos == min_pos && it->method != GET_FROM_BUFFER)
+ else if (LIKELY (max_pos == min_pos && it->method != GET_FROM_BUFFER))
/* A line that is entirely from a string/image/stretch... */
row->maxpos = row->minpos;
else
@@ -25210,7 +25211,7 @@ display_string (const char *string, Lisp_Object lisp_string, Lisp_Object face_st
}
break;
}
- else if (x + glyph->pixel_width >= it->first_visible_x)
+ else if (LIKELY (x + glyph->pixel_width >= it->first_visible_x))
{
/* Glyph is at least partially visible. */
++it->hpos;
@@ -27847,7 +27848,7 @@ produce_special_glyphs (struct it *it, enum display_element_type what)
spec_glyph_lookup_face (XWINDOW (it->window), &glyph);
}
}
- else if (what == IT_TRUNCATION)
+ else if (LIKELY (what == IT_TRUNCATION))
{
/* Truncation glyph. */
SET_GLYPH_FROM_CHAR (glyph, '$');